Somewhat similar to the way cars are capable of operating in different gears, you have a couple of different options for drive modes when it comes to your camera, and as you're about to see, they're pretty self-explanatory.
Single (One) Shot
In single shooting drive mode, the camera takes one photo each time you press the shutter button. Plain and simple. This is where the camera is set to default and where it will likely spend most of its time.
If you're shooting a wildly moving subject or trying to catch a specific moment in action—the very moment your kid scores the winning soccer goal, for example—you can up your chances of success by using continuous shooting mode to essentially turn your camera into a rapid-fire machine gun. As long as you continue to hold the shutter button down, your camera will happily fire away.
The number of frames per second that your camera is capable of capturing will vary from model to model, but either way, it's pretty impressive. With the camera's drive mode set to continuous (and the focus mode also set to continuous, thereby tracking moving subjects), I was able to capture a series of frames as my subjects blew past my lens, seen in Figures 4.16 - 4.18.
Figure 4.16 The first of three images in a series, captured using continuous drive mode.
Figure 4.17 The second of three images in a series, captured using continuous drive mode. Of all three frames, this one is my favorite. If I had shot in single shot drive mode, I would've had to rely on perfect timing to score this. Continuous drive mode is much, much easier!
Figure 4.18 The third of three images in a series, captured using continuous drive mode.
You may be wondering why you wouldn't just leave your camera set to continuous mode all the time. While you could, you'd quickly find yourself firing off five or more frames when you mean to shoot only one, rapidly piling up on your memory card and wasting space on your hard drive later.
So, while continuous shooting is great for catching key moments in sports or other action shots, having your camera operate like a machine gun is overkill for most situations and tends to get old quickly. And—even if you wanted to—continuous drive mode doesn't mean you can hold the button down for hours on end and take 10 bazillion shots in a row without interruption.
Your camera can only fire off a certain number of photos in a single round (called a "burst") without having to pause to catch its breath as each photo must be stored in active memory until it can be written to the memory card. The memory buffer is only so big and can only handle so many photos at a time—regardless of the camera's frame-per-second rate. If you attempt to hold the shutter button down for extended periods of time, the camera will eventually be forced to suspend shooting to clear the buffer memory before it can continue.
The bottom line? Stick to single shot drive mode for most things, and make use of continuous when you really need it.